Embodiments relate generally to very-large-scale integration (VLSI) integrated circuits, and, more particularly, to low-noise arrangements for VLSI differential input/output (I/O) structures.
Integrated circuits are becoming increasingly complex. For example, in VLSI integrated circuit (IC) design, there has been a trend towards increasing die sizes, numbers of circuits, compaction of circuits, etc. Such increases tend to increase the complexity of interfacing with those ICs. For example, interfacing with higher numbers and densities of signals being communicated to and from the circuits of the IC can involve higher numbers and densities of pins, solder bumps, and/or other vertical I/O structures.
Often, there is also a desire to operate ICs with high signal integrity, which can be difficult with large numbers of densely arranged I/O structures. For example, many I/O signals can be communicated as differential signals (e.g., by pairs of pins), which can permit more noise tolerance because much of the noise can be common mode and can be rejected by a receiver having good common-mode rejection properties. However, densely arranged I/O structures can experience appreciable amounts of coupling (e.g., cross talk) from adjacent I/O structures, and such coupling can increase at higher frequencies.